The article Wilkinson et al, ‘Process site emission quantification and location from optical remote sensing measurements’ Proc. SPIE-Int. Soc. Opt. Eng; 1996, Vol. 2883, pages 355-364 discloses such a method.
Such method contains the steps of:    (a) selecting a set of measurement locations;    (b) measuring the concentrations of the emanations in the intervening medium at the measurement locations to obtain a set of observed data;    (c) measuring the velocity of the intervening medium at a location;    (d) postulating a dispersion model that allows the calculation for a position of the concentration of the emanation arising there from a source;    (e) postulating a set of source models consisting of source parameters, such as the position(s) of assumed source(s), and assumed emission rate(s);    (f) calculating with the dispersion model for each postulated source model the concentration that would arise at the measurement location(s) to obtain a set of synthetic data for each postulated source model;    (g) comparing the set(s) of synthetic data with the observed data to select the source model that gives the closest fit; and    (h) outputting the position and emission rate of the at least one source assumed in the source model that gives the closest fit.
The measurements carried out to obtain the set of observed data were done using open-path measurements. In the open-path measurements, the concentration of emanations is measured over a path having a length of up to 500 meters by means of a sensor to yield a path-integrated gas concentration measurement.
This method was applied on a refinery to locate gaseous leaks and their associated mass release rates (emission rates). The relatively low concentrations typically resulting in the atmosphere from such leaks require long measurement paths for the influence of the sought gas or gases to be measurable. However, because the concentration is detected along the full length of a line, the likelihood: that emanations from a source would be detected is relatively high.
A disadvantage of the known method is that it is laborious to set up the devices needed to carry out the open-path measurements.